Water isn't weak, lol. It's the best class later. This game has existed multiple times in various forms over the past few years with the same mechanics, dailies, and ninjas.

Later Water will be awesome. For one thing the element of Water is only weak to Earth. How many Earth people have you seen walking around? I'm sure you've seen TONS of Fire guys though (and you wreck them).

But more importantly it's the survival aspect and chakra control. Late game surviving is all that bloody matters because unless you paid to win you're not one-shotting everyone anymore. It's also extremely good in Arena where item bonuses make no difference. But for water to really shine she needs to be upgraded a ton and it won't be till about level 70 that you see she's freaking OP.

I went with Lightning this time because I remember the hellish Water grind and it's not worth doing that all over again. If you pay money it is though, you'll be much stronger team late game.